Chemical "Double Slits": Dynamical Interference of Photodissociation Pathways in Water
R. N. Dixon,
1*
D. W. Hwang,
2
X. F. Yang,
2
S. Harich,
2
J. J. Lin,
2
X. Yang
2
Photodissociation of water at a wavelength of 121.6 nanometers has been investigated by using the H-atom Rydberg tagging
technique. A striking even-odd intensity oscillation was observed in
the OH(X) product rotational distribution. Model calculations
attribute this oscillation to an unusual dynamical interference brought about by two dissociation pathways that pass through dissimilar conical
intersections of potential energy surfaces, but result in the same
products. The interference pattern and the OH product rotational
distribution are sensitive to the positions and energies of the conical
intersections, one with the atoms collinear as H-OH and the other as
H-HO. An accurate simulation of the observations would provide a
detailed test of global H2O potential energy surfaces for
the three (
/Ã/
) contributing states. The
interference observed from the two conical intersection pathways
provides a chemical analog of Young's well-known double-slit
experiment.
1 School of Chemistry, University of Bristol, Bristol
BS8 1TS, UK.
2 Institute of Atomic and Molecular Sciences,
Academia Sinica, Taipei, Taiwan 106, R.O.C.
*
To whom correspondence should be addressed. E-mail:
r.n.dixon{at}bristol.ac.uk
Permanent address: Laboratory of Plasma Physical Chemistry,
Dalian University of Technology, Dalian 116024, China.
